For those expecting Manziel's prolific rushing exploits to translate into a blazing 40-yard dash like the 4.41 that Robert Griffin III turned in when he participated in the combine in 2012, Manziel's time might not be too impressive. But it's Manziel's quickness and change-of-direction skills that make him such a dangerous runner, and the time he ran showed more than enough speed for NFL scouts to know he can be plenty dangerous on the run in the NFL.

Manziel took a swig of Gatorade before his 40 tries and spoke briefly with NFL Hall of Famer Michael Irvin when he finished. His private coach, George Whitfield, took to Twitter after he ran to express his excitement for the unofficial time of 4.56.

Manziel's didn't end up with the best time among all quarterbacks. That distinction went to Virginia Tech's Logan Thomas, who ran a 4.61.

Just behind Thomas were Miami's Stephen Morris (4.63) and South Carolina's Connor Shaw (4.66). Fresno State's Derek Carr turned in a 4.69, Northern Illinois' Jordan Lynch ran a 4.76 and Clemson's Tajh Boyd was clocked at 4.84. Central Florida's Blake Bortles ran a 4.93. Bortles is considered one of the draft's top three prospects at the position along with Manziel and Teddy Bridgewater of Louisville, who chose not to run.